1. Field of the Invention
This invention relates generally to cargo containers, and more particularly concerns a cargo container for aircraft or seagoing vessels that has flexible, explosion resistant side walls and a flexible, explosion resistant door that are capable of expanding to substantially contain an explosive blast within the container.
2. Description of Related Art
Conventional cargo containers for aircraft and seagoing vessels are typically not constructed to resist and contain explosive blasts, making such containers vulnerable to deliberate bombings and accidental explosions of materials being transported in such containers. Cargo containers for seagoing vessels can be made of a heavier, sturdier construction in order to withstand internal explosions, but it is typically not practical or economical to use such heavy cargo containers in aircraft, for which weight reduction is an important consideration.
In one approach to making cargo containers explosion resistant, the cargo container is hardened, being formed of flat Kevlar and resin panels joined together along their peripheries. The corners are reinforced by making them of a greater thickness, and the construction provides many layers to withstand an explosion.
Another approach to providing a explosion resistant cargo container provides a strong lightweight double-walled reinforced vessel having an intermediate single woven member formed from Kevlar, graphite or fiberglass, and disposed between spaced apart first and second walls. The intermediate woven member comprises a plurality of longitudinally extending cylindrical members positioned parallel to each other and a plurality of generally parallel fibers woven about the cylindrical members and extending perpendicularly to the cylindrical members. The woven layer is bonded between the first inner wall and the second outer wall with resinous materials.
Another collapsible storage container for the transportation and storage of goods which otherwise could not be stably stacked is formed of all Kevlar or other materials. The container is formed of four walls hingedly connected together, the walls being formed by frames made from welded sections of rectangular hollow section steel with infill panels of a mesh such as Kevlar. A roof member is formed from a frame and a mesh infill panel in the same manner as each of the walls, and L-shaped brackets on the walls captively engage a pallet underneath the container.
Another known aircraft cargo container that is capable of expanding to facilitate containment of an explosive blast is formed of panels fastened together at the corners to form a container capable of expanding to facilitate containment of an explosive blast. The top and side panels are formed of knitted aramid material, and are joined to each other at edges and corners. The knitted aramid fibers are sandwiched between layers of foam material sandwiched between an inner skin comprising a fiberglass layer bonded to a sheet of PVF, PVC, or polyurethane, and an outer aluminum skin. The inner skin is a two-layer material of open weave glass fiber impregnated with a resin and bonded to a thin sheet of polyvinyl fluoride or the like. To enable the edges of the panel to be connected to other panels or the door frames of the container and to provide a secure anchorage for the Kevlar sheets, the outer aluminum skin is formed around its edges with one flange being securely connected to another similar flange of the corner joint extrusion by uniformly spaced rivets or bolts which also penetrate through all the other layers of the panel.
Another known explosion resistant cargo container is formed from a structural sandwich panel made of many layers of Kevlar. The sandwich panel is made of rigid structural face sheets and a hybrid core of rigid rod members which pierce and cross through layers of soft, dry, energy-absorbing material. The soft energy-absorbing material of the core can be made of several dry layers of woven ballistic fabric from aramid fibers such as Kevlar. Graphite epoxy yarns are also sewn through the Kevlar fabric plies and the epoxy resin cured to rigidize the sewn cross-through members. The edges of the material were sewed and impregnated along the edges with epoxy resin for mounting in a frame.
It has however been found that while explosion resistant panels of various types can typically be made strong enough to contain an explosion, the seams along the frame where the panels are connected are typically the weakest point of the container in an explosion. There thus still exists a need a blast resistant cargo container with flexible, explosion resistant side walls for substantially containing the force of an explosion within the cargo container, that is relatively lightweight, with reinforcement of the seams along the frame where the panels are connected that are otherwise commonly the weakest point of the container during an explosion. The present invention meets these needs.